The goal of this proposal is to obtain support for the acquisition of a centralized system for automated synthesis of homogeneous peptides. The requested instruments are a 430A peptide synthesizer, a preparative chromatography system Prep LC 3000 for purification of peptides and a Picotag system for the determination of amino acids in hydrolysates. Peptides as delivered by the synthesizer are not of sufficient homogeneity to be used for biological experiments and a purification capability is an essential component of the system. Quality control of the purified peptides involves their hydrolysis with acid or enzymes followed by quantitative amino acid analysis. Thus, although three instruments are requested the system must be regarded as a unit. Specific areas of investigation which would benefit from the availability of synthetic peptides include their use as: antigens for raising monoclonal antibodies (Hofmann, Ho, Hempel, Jones), probes to elucidate the action of C. perfringens enterotoxin (McClane), tools to study the regulation of the contraction of isolated brush borders (Collins), and tools to study hormone action (Robinson). As the facility becomes operative, it can be expected to attract additional users.